Australia's unconditional support for the Sri Lankan government leaves us isolated from our allies and further than ever from assuming the mantle of the regional human rights leader.

As the Commonwealth summit focuses international attention on Sri Lanka this week, a growing chorus of nations including Britain, Canada and India have expressed their concern about the grave and ongoing human rights abuses in the country.

Canada's Prime Minister Stephen Harper took the first strong stand and declined the invitation to attend, saying that the Commonwealth was “accommodating evil” by letting Sri Lanka host the meeting.

Since the bloody end of its civil war in 2009, there have been growing calls for accountability for the ruthless and brutal tactics that brought the war to a close.

A UN panel of experts has reported that 40,000 people died in the final stages of the war and that there was credible evidence of war crimes and crimes against humanity committed by government forces as well as the Tamil Tigers.

Calls for accountability have grown louder ahead of CHOGM. Last weekend, British Prime Minister David Cameron watched No Fire Zone: In the Killing Fields of Sri Lanka, a film that chronicles some of the alleged war crimes, including deliberate shelling of civilians, hospitals and the United Nations by government forces.

In a tweet, Cameron described the film as a “chilling documentary” and promised to put serious questions to the Sri Lankan President, Mahinda Rajapaksa, at CHOGM.

Sri Lanka's civil war may be over, but the conflict and suffering are not. This week BBC's Newsnight broadcast more evidence of widespread and systematic rape and torture of Tamil detainees that occurred in 2013.

On Monday, the Indian Prime Minister Manmohan Singh announced that he would not be going to CHOGM either.

Meanwhile, Sri Lanka is scrambling to silence any potential critics. In a piece of heavy-handed censorship, Sri Lanka banned members of an international law delegation from entering the country and has denied entry to countless journalists who applied for visas to cover the Commonwealth summit. Sri Lanka is one of the most dangerous places in the world to be a journalist.

This week, Australian senator Lee Rhiannon was detained by Sri Lankan authorities for questioning at the end of her fact-finding mission to the country.

While this treatment of international visitors is rare, it is an everyday reality for many Sri Lankans.

UN human rights chief Navi Pillay recently said that there were real risks of reprisals for any dissent or criticism of the government. She raised concerns about the “huge levels of insecurity, fear and surveillance” of the Sri Lankan population.

The rule of law is so eroded in Sri Lanka that people who are harmed by government actions no longer expect redress, justice or accountability from the judiciary. The Chief Justice herself was not protected and was unconstitutionally impeached in January this year.

As other nations intensify their condemnation of Sri Lanka's recent human rights record ahead of CHOGM, Australia has oscillated between silent acquiescence and express approval of Sri Lanka's government.

The rationale given for the Australian position is that engagement with Sri Lanka is the best model. The real reason, unashamedly acknowledged by Prime Minister Tony Abbott himself, is that Sri Lanka co-operates in taking back people arriving by boat and Australia needs to maintain “the best possible relations” there.

The Australian government asserts a false choice between boycotting CHOGM and engaging with Sri Lanka.

In fact Australia could engage by sending a downgraded delegation, as Canada and India are doing, while denying Sri Lanka the prestige of standing as equals with all Commonwealth leaders.

Cameron has said that “diplomacy is not about ducking difficult discussions” and that the right thing to do is engage at CHOGM and “shine the international spotlight on the lack of progress in the country”.

For Abbott to attend and not raise human rights concerns would be craven. His justification for not speaking up – that he doesn't want to “trash” the Commonwealth – is insulting to Britain, India and Canada, which have recognised that engagement with Sri Lanka and principled defence of human rights are not mutually exclusive.

Abbott overlooks that the very purpose of the Commonwealth is to protect human rights and the rule of law.

It's time for our Prime Minister to accept that Australia's identity is formed by our actions and statements abroad. By failing to defend human rights and the rule of law in Sri Lanka, it is Abbott who trashes Commonwealth values and Australia's reputation as a fair, free, principled nation that upholds the rule of law and human rights.

If we don't stand against war crimes and crimes against humanity resulting in the death of 40,000 people, what do we stand for?

Emily Howie is the Director of Advocacy and Research at the Human Rights Law Centre. She is on Twitter @emilyhowie

Human Rights Law Centre

The HRLC is an independent, not-for-profit organisation which protects and promotes human rights in Australia and beyond through a strategic mix of legal action, advocacy, education and capacity building.